i used to run on dialup and hated how long it took
for some things to download. the package debdelta
did help some at that time, but i have no idea if the
service is even still there let alone functional.

I installed Gentoo once over dialup
It took two weeks.

i used to take the USB stick to the library to download
big packages when needing updates. glad i haven't had to
do that in a while, but i still have a relatively slow
connection (about 10M/minute) compared to many, but it's
much better than dialup.

think I did that once to build Scribus, tracking down the dependencies
was a nightmare.